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Science Is Sexy: DNA You Say?

Much of the time, when I discuss science with non-science people, I get the impression that genetics is a double-edged sword for them. While most understand that genes contain the “blueprint” for the organism that carries them, and that heredity somehow factors into that, the DNA (DeoxyriboNucleic Acid) molecule and its role in the process remain a mystery. Hopefully we can begin to clear things up here.

Each cell in your body (excluding red blood cells) contains a highly condensed package of DNA. While the structure of this package is unimportant for our purposes, one good thing to remember is that whenever a bit of DNA needs to be used by the body, that part can be selectively accessed and then repackaged again. Also, whenever the cell divides (and makes a complete copy of itself), ALL of the DNA needs to be “replicated,” or copied, as well.

This is a very important process because there is a LOT of DNA that needs to be copied and moreover it needs to be copied ACCURATELY. DNA and RNA (RiboNucleic Acid), are relatively similar molecules in that they can both store information, but the machinery for copying RNA is much more error prone, so in higher organisms, DNA is the main information molecule.

As a molecular biologist fresh out of undergrad, I COULD describe to you all of the wonderful nuances in DNA replication, but I’m guessing you’d rather see a video instead. Keep in mind that as far as we can tell, this simulation of replication is real-time. This is litterally happening all over your body all the time:

So why all this fuss about DNA in the first place? Well, as I said before, DNA is the body’s information storage system. Each base pair (the rungs on the ladder in the image up top) represents a position in the “language” of genetics. Since we’re on a tech blog, relate it to binary code. Each 1 or 0 doesn’t have any intrinsic meaning unto itself, but several of them in a row represent a value of some sort. The same goes for these base pairs.

Also like binary, DNA is not the only language at work in the system. Where hexadecimal and higher computer languages work as an overlay to make binary more approachable by human users, RNA and proteins are the actual “interface” by which the body accesses the information stored in your DNA. The process of rewriting DNA into these “higher languages” is a multi-step process.

The basic progression of DNA to RNA to Protein is known as “central dogma” and its development was an extremely important step in molecular biology. It simply states that in DNA based genomes (as opposed to those of some viruses), genetic information generally flows from a DNA format to a protein format and that proteins do not send that information back the other way. While we are now learning that genetic information can undergo a number of alternate routes (mostly involving RNAs with their own functions), the revolution that followed central dogma should not be forgotten.

To learn more about DNA and genetic dogma, check out this wonderful article on Wikipedia. While some argue that the wiki format makes it less reliable, the group of scientists who patrol the science articles on Wikipedia is fairly robust and I’ve always found the information to be quite sound.

Since this is one of the more “molecular” articles I’ve written, it was hard to go into too much detail. If you want a little explanation about anything in particular, feel free to ask me on Twitter or leave your question in the comments!

Check out the discussion of records and record players in Hofstadter's book "Godel, Escher, Bach: The Eternal Golden Braid". It's an interesting chapter on how DNA is "played back" through an extremely complicated record player to transform the genotype into its phenotype. The philosophical question raised is how much of the information is in the record, and how much is in the record player? If you sent a molecule of DNA to an alien civilization, is there, in principle, enough information present to reconstruct the phenotype?

Check out the discussion of records and record players in Hofstadter’s book “Godel, Escher, Bach: The Eternal Golden Braid”. It’s an interesting chapter on how DNA is “played back” through an extremely complicated record player to transform the genotype into its phenotype. The philosophical question raised is how much of the information is in the record, and how much is in the record player? If you sent a molecule of DNA to an alien civilization, is there, in principle, enough information present to reconstruct the phenotype?